This invention is an improvement over the hand tools contained in U.S. Pat. No. 5,176,049 issued to applicant on Jan. 5, 1993, entitled "COMPOUND LEVERAGE GRIPPING TOOL WITH CONSTANTLY PARALLEL JAWS".
The improvement consists of a combination of all the outstanding features contained in the above referenced documents to provide a single tool having all of those features as follows: (a) can be adjusted quickly and automatically; (b) constantly parallel jaws; (c) can be used in a fast, ratchet-like manner; (d) can be locked on an object very simply and effectively; and (e) can automatically be released from a locked position by just squeezing the two handles.
A locking tool and numerous copies of it have been on the market for over 50 years, but they have a number of disadvantages not present in the instant invention. The dominant locking tool is contained in U.S. Pat. No. 2,280,005, issued to Petersen Apr. 14, 1942. The locking means utilized in the present invention is superior to that used by Petersen and his copiers as will be obvious from the description and claims presented herein.
The first of these disadvantages is the manner in which the jaws are adjusted to an object. In making such an adjustment, a threaded screw is located in the extreme end of one of the handles. In order to adjust the jaws to an object, this screw must be turned inward to widen the jaw gap and outward to narrow the jaw gap, a procedure that must be done several times before the proper jaw gap is obtained. For every object of a different size, the jaws must be adjusted precisely in order for the locking operation to satisfactorily take place. This results in a tedius and time-consuming operation.
A second disadvantage occurs when the tool is adjusted so that the lock is extremely tight on a work object. When this occurs, it is very difficult to squeeze the release mechanism hard enough to effect the release, and very often the handles fly apart very abruptly and can injure the user's fingers and cause him to drop the tool.
A third disadvantage lies in the fact that the tool is difficult, if not impossible, to use as common ordinary pliers or wrench because the spring attached to the pivoting adjustable jaw and to the handle containing the fixed jaw urges the handles to spring apart and spread the jaws out of position for the job at hand as the jaws cannot maintain a fixed opening without being locked. This feature not only is frustrating to the operator, but is also time-consuming.
Other attempts have been made to eliminate the screw adjustment of the basic patent issued to Petersen, but they have all been failures as the Petersen tool is still the predominent tool in this field after more than fifty years. For example, the U.S. Patent issued to Westby etal, U.S. Pat. No. 3,208,319, Sep. 28, 1965, which has a large number of parts that would be difficult to make and assemble, plus having a cam lever or an adjusting screw projecting outwardly from one or the other of the two handles, presenting a very uncomfortable grip for the user.
Another example is U.S. Pat. No. 3,793,914, Feb. 26, 1974, issued to Helms, which has a finger tab 43 projecting outwardly from one of the handles, presenting the same problem as the Westby etal invention.
Another disadvantage found in all three of the inventions discussed above is that they all have jaws that "scissor" in order to open and close them on an object, which means that there is only one point in the adjustment range of the jaws where they are parallel to each other in the optimum gripping position.
As can be seen, no such proliferation of parts or disadvantages exist in the present invention.
Accordingly, several objects and advantages of the present invention are to provide:
(a) a hand tool that can be operated with a fast, ratchet-like action without the use of a standard ratchet mechanism, and which can be locked on an object of round, square, hexagonal, or irregular shape; PA1 (b) a hand tool of various jaw configurations having a compound gripping leverage ratio of at least 8-to-1; PA1 (c) a hand tool that has jaws which are always in parallel alignment throughout their entire adjustment range; PA1 (d) a hand tool that automatically adjusts the jaw gap by the squeezing and relaxing of the grip pressure on the handles; PA1 (e) a hand tool whose jaws can easily be locked on an object with either a light or a strong grip at the choice of the operator with just a flick of the thumb of the hand holding the tool; PA1 (f) a hand tool that can be released from said locked position automatically by just squeezing the two handles together; PA1 (g) a hand tool that can be operated as an ordinary plier or wrench without interference or problems caused by the adjusting, locking, or releasing mechanisms; and PA1 (h) a hand tool as described that can be produced and sold economically to a wide spectrum of the population.
Other objects and advantages appear in the combination of the elements, arrangement of the various parts, and unique features of construction and usage which will be pointed out more fully hereinafter and disclosed in the accompanying drawings and detailed description wherein some preferred forms of the invention are presented.
It will be understood that these preferred forms are for illustration purposes only and the invention is not necessarily limited to such, but may be adapted and used for any purpose for which it is found to be suitable.